Walrus

The single species of walrus resembles the sea lions in that its hind flippers can be brought forward in order to help it move on land. However, it cannot move as fast or adeptly as sea lions, and will often just drag itself forward.

These massive members of the seal family are unmistakable. Their distinctive long tusks - actually modified canine teeth - are present in both sexes.

Walruses live among the ice floes of the Arctic Ocean. These huge sea mammals are well known for their long tusks, which they use to stab opponents during fights. Walruses also use their tusks to "haul out", or pull themselves on to floating ice, and sometimes hook themselves to floes so that they can sleep while still in the water.

Walruses use their whiskered snouts to root out prey and blast away sediment with jets of air squirted from the mouth. They tackle shelled prey by holding them in their lips and sucking out the soft bodies.

Walruses live in large herds, sometimes of many thousands. In winter they feed in areas of thin sea ice, avoiding thick, unbroken ice, which they cannot break through from beneath. In summer, when the ice recedes, they spend more time on land.

Walruses have long tusks growing out of the upper jaw. Males, which are twice the size of females, also have longer tusks. Their bodies are reddish-brown and sparsely covered in coarse hairs. Males have two air pouches inside the neck, which they use to amplify their mating calls.

Male walruses, called bulls, will battle ferociously with each other on land for mating rights during the breeding period. Mating takes place in the water, and calves are born on the ice 11 months later. The young stay with their mothers for three years.

They can inflict serious injuries with their tusks, with the largest individuals usually proving to be dominant. In the sea they can dive to depths of 75 m (250 ft) in search of food, relying on their whiskers to locate prey on the seabed. Walruses face few dangers, although they are at risk from killer whales. Polar bears represent a threat, too.

Distribution: Occurs in the Pacific, off Alaska and in the Chukchi Sea. Atlantic population extends from northern Canada to Greenland. Both populations move south in winter.